1) Field of the Invention
The present invention relates to apparatus for making cord structure for use in the reinforcement of pneumatic tires, hose, belts and other articles generally known as mechanical rubber goods. The invention also relates to a method for operating such equipment to form a hybrid yarn.
In particular, the invention describes a process for producing a cord from a supply of three yarns where one of the yarns is different. More particular, the process employs a modified cabling machine using two yarns on a reel and a third yarn from a spindle pot.
2) Prior Art
It is known in the art to have two and three twisted filament yarns twisted together to make a cord. However, at least 85% of the market consists of two twisted filament yarns twisted together to form a cord.
Twenty years ago ring twisters were the conventional equipment used first to twist the yarn filaments, and then to twist these twisted yarns (2 or 3) together to form a cord. The ring twisters had two operations, namely plying (twisting the yarns) and cabling (twisting the twisted yarns). Then in the early 1990""s, commercially available cabling machines entered the market which twisted two yarn filaments together to form a cord in a single operation. Cabling machines became more popular because they eliminated one step from the ring twister process. Three filament cords are still made with ring twister apparatus.
An article by Helmut Weisser and Milan Czapay set forth in Technical Textile International and published in 1992, pages 20 to 28 discloses twisting systems for tire cords. The article discusses a classic ring twisting system and the new design apparatus labeled as xe2x80x9cdirect cablingxe2x80x9d. This article discloses yarns from a creel bobbin and a spindle pot bobbin which are twisted together to form a cord. This article concludes that the cabling process using direct cabling equipment xe2x80x9cis not suitable for the production of 3 or multi-ply yarns.xe2x80x9d
An article titled xe2x80x9cCabling of Tire Cord, the Process for Now and the Futurexe2x80x9d by Hanz Schellenberg as published in Textile Technology, January, 1995, pages 41-43 also discloses the direct cabling process and states that these type cablers can cable nylons, polyester, rayon, and aramid.
U.S. Pat. No. 4,932,198 by Eisenhauer, et al. discloses a cabling machine having a creel, a spindle motor, a spindle pot containing a feed bobbin, and feeding the yarn upwardly through the spindle motor and around the spindle such that it can be twisted with yarn exiting from the spindle pot.
German Patent (Auslegeschrift) 1,162,239 having a patent date of Jan. 30, 1964 and assigned to Pirelli Tire Company discloses a direct cabling machine (and is one of the older disclosures for tire cord), and has a priority date based on an Italian patent of Jun. 6, 1957. This patent discloses a bobbin of yarn which is fed through the central part of a spindle such that it rotates to form a xe2x80x9cballoonxe2x80x9d around the spindle pot containing a second fiber and these two yarns are twisted together to form a tire cord.
European Patent Application 0,165,188 published on Dec. 18, 1985 and issued to Charbonnier also discloses a direct cabling machine but does not disclose a creel for the first yarn.
There exists a need in the market for a new and improved direct cabling system capable of twisting three yarn filaments together to form a cord substantially employing existing direct cabling equipment. In particular, there exists a need in the art to cable three yarn filaments together wherein one of the yarn filaments possesses a significantly smaller denier than the other two yarn filaments.
There also exists in the art a need for three yarn filaments twisted together to form a cable wherein one of the yarn filaments is of a different material.
In the broadest sense, the present invention comprises a process for producing a cord comprising providing a supply of at least three yarns wherein one of said yarns is different, and twisting all the yarns together to form a cord. The different yarn has a smaller denier and/or is a different polymer than the other yarns.
In the broadest sense, the present invention also comprises a process for producing a cord comprising providing at least two yarns tangled together, providing at least third yarn in a spindle pot, feeding at least two yarns through a rotating portion of the spindle and around the spindle pot to a twister, feeding the third yarn from the spindle pot to the twister, and twisting all the yarns together to form a cord. This process also contemplates that one of the at least two yarns tangled together has a smaller denier and/or is a different polymer than the other yarns.
In the broadest sense, the present invention also relates to an apparatus for producing a cord, comprising a creel containing at least two yarns, a spindle having a rotating portion and a stationary portion, the stationary portion at least containing a third yarn, the rotating portion rotating the yarns from the creel, and a twister for twisting the yarns from the creel and the third yarn to produce a cord.
It is an object of the present invention to produce a hybrid cord consisting of three yarn plies wherein one ply is of different material and/or has a substantially smaller denier than the remaining two plies.